Using the API I am able to enumerate all my devices, read the current status and get current values e.t.c but can someone explain the logic behind ' getDeviceChannelLog'? I can get the log for say 'PowerLevel' by giving a start and stop unix timestamp but cannot figure out the logic it uses. For example:

Are these readings that are waiting to be uploaded to the web?
What is the sample interval?
Are these samples or average values between samples?
Why don't repeated calls with the same parameters give the same response?